The invention relates to rotary transformers.
Aircraft deicing is an important safety consideration. In addition to the apparent need to deice the wings and leading edges of the various airfoil surfaces, many aircraft also provide for deicing the propellers for conventional prop engines and/or turboprops. Deicing the propeller blades presents a particularly challenging design approach due to the propeller rotational speeds and hostile environmental conditions.
A known deicing technique involves the application of high energy impulses to the airfoil or propeller surface. These high energy impulses can be, for example, pneumatic, hydraulic or electro-motive or a combination thereof. Regardless of the type of force applied to the surface to be deiced, electrical energy pulses are usually needed for impulse deicing of propellers. In addition to impulse deicing, propellers are commonly deiced with thermal deicing systems. The electrothermal systems do not necessarily require short duration electrical pulses, but may require energy transfer on the order of 3000 watts, for example.
The main power source for aircraft deicing systems is the aircraft engine power plant. A device is needed to couple the electrical energy from the engine to the high speed rotating prop. Conventional systems use brush and/or slip-ring assemblies to achieve the rotary power coupling. But, such apparatus tend to exhibit mechanical wear of the brushes and rings. Thus these assemblies require costly down time for repair, maintenance or replacement of the brush/slip-ring assembly.
The need exists, therefore, for a rotary electrical power coupling device that is low maintenance and has weight and size parameters suitable for aircraft deicing systems. In a more general sense, the need exists for a rotary transformer that is lightweight and small yet is capable of coupling high energy and power between rotating and stationary cores.